Maternal origins, population structure and demographic history of ten Chinese indigenous goat breeds from Yunnan

Ecogroups and maternal haplogroups reveal the ancestral origin of native Chinese goat populations based on the variation of mtDNA D-loop sequences

China is rich in goat breeding resources. Officially recognized local goat breeds are mainly distributed in agro-ecological regions. The population structure and matrilineal origin of native Chinese goats can be used to formulate protection and utilization strategies for these genetic resources. In this study, the genetic structure and maternal origin of native Chinese goats were investigated using mtDNA D-loop sequences. A total of 329 goat samples from 25 Chinese indigenous goat populations and five introduced goat breeds from abroad were collected; these populations were distributed in four ecogroups designated as Southwest, South-central, the North China Plain, and Foreign-ecogroup. A larger average number of nucleotide differences and richer nucleotide diversity were observed in South-central and Foreign-ecogroup, whereas these were lower in Southwest. The 216 haplotypes divided into several haplogroups, of which HapA contained 99 haplotypes distributed in Southwest, the North China Plain, and Foreign-ecogroup with high frequency (0.53-0.77), whereas the frequency of HapA in South-central was <0.09. HapB was mostly found in South-central (0.5538) and was distributed to the North China Plain (0.2667), while it was rare in Southwest (<0.08) and Foreign-ecogroup (<0.07). According to the estimation of kinship and ancestry, HapA had five ancestors (A2, A3, A5, A10, and A12), HapB had a single maternal ancestor (A8), and HapC had two maternal ancestors (A1 and A4). This study showed that native Chinese goat breeds were mainly divided into three haplogroups (HapA, HapB, and HapC) and goat populations have expanded in the ecological regions.

Analysis of World-Scale Mitochondrial DNA Reveals the Origin and Migration Route of East Asia Goats

Despite much attention on the history of goat evolution, information on origin, demographic history, and expansion route remains controversial. To address these questions, we collected 4,189 published goat DNA sequences including 1,228 sequences from 57 breeds in China and 2,961 sequences including 193 goat breeds from 71 other countries and carried out an integrated analysis. We found goat breeds from South China had the highest genetic diversity of lineage B, and subclades B2 only were found in Southwest China, suggesting that lineage B (particularly, subclade B2) probably originated from Southwest China and its surrounding areas. In addition, in this study, we found that lineage A from South China also presented higher genetic diversity and earlier expansion time (10, 606 years ago), even earlier than breeds from the Middle East. Hence, we speculated that South China and surrounding areas were the origin of lineage B and also the transportation hub for lineage A spreading to North China and Southwest Asia. Furthermore, according to the analysis of correlation between genetic differentiation value λ1 and λ2 and geographical distance, we further confirmed two phases of migration in goat breeds of North China. These results will contribute to a better understanding of the origin and migration history of domestic goat.